A sample of 10 diesel trucks were run both hot and cold to estimate the difference in fuel economy. The results, in mpg, are presented in the following table. (From €œIn-use Emissions from Heavy-Duty Diesel Vehicles,€ J. Yanowitz, Ph.D. thesis, Colorado School of Mines, 2001.)

Find a 98% confidence interval for the difference in  mean fuel mileage between hot and cold engines.

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Truck Cold Hot 4.56 4.26 2 4.46 4.08 6.49 5.83 4 5.37 4.96 6.25 5.87 5.90 5.32 4.12 3.92 3.85 3.69 9. 4.15 3.74 10 4.69 4.19